In fire suppression systems requiring a high mass flow rate of extinguishant, for example in order to quench an incipient fire in the presence of a highly volatile liquid fuel, it is known to achieve the required rapid discharge of extinguishant from a container, by opening a relatively large bursting diaphragm fitted to a venting port of the container, thus permitting the contents to be ejected either by the vapour pressure of the extinguishant, or by the pressure derived from other means, for example an additional gas filling. Burstable containers of this kind have been proposed for use, for example, in aircraft fire suppression systems. However, such burstable containers have the disadvantage that the high mass flow rate of the fire extinguishant discharged therefrom can cause unduly high reaction forces to be imposed upon the container and thus upon the mountings by which it is secured in, for example, an aircraft, which reaction forces may possibly lead to failure of the mountings and damage to the adjacent structure of the aircraft. cl SUMMARY OF THE INVENTION
It is an object of the present invention to eliminate, or at least to reduce, the above mentioned disadvantage of the known fire extinguishers referred to.
The present invention provides a fire extinguisher comprising a container providing a source of extinguishant, burstable means defining a part of said container and permitting, upon bursting thereof, a high mass flow rate of extinguishant from the container, and venting means defining a plurality of outlet ports through which extinguishant flowing from the burstable part of the container may be discharged, the number, size and position of the said discharge ports being balanced in such a manner that the reaction forces upon the container due to the flow of extinguishant from the discharge ports substantially balance one another. Thus the resultant force upon the container is reduced or eliminated.
According to one embodiment of the invention, the said venting means comprises a generally circular end cap overlying a circular burstable diaphragm closing said container, said end cap comprising an even number of radial outlet ports regularly angularly spaced around its periphery whereby each outlet port is balanced by a corresponding port diametrically opposed thereto.
According to a further, preferred feature of the invention the said outlet ports are associated with deflector plates for deflecting said extinguishant axially with respect to said circular end cap, the said deflector plates of alternate ports being angled in opposite directions, whereby the axial reaction forces due to discharge of extinguishant from alternate ones of said outlet ports are balanced by an oppositely acting axial force due to discharge of extinguishant from the remaining ports.